Johann kottach



UNITED STATES ATENT OFFICE.

JOHANN ROTTACH, OF VIENNA, AUSTRIA-HUNGARY.

TRANSFER-SURFACE FOR LITHOGRAPHIC PURPOSES AND MANUFACTUilE OF SAME.

SPECIFICATION forming part of Letters Patent No. 614,029, dated November8, 1898.

Application filed January 15, 1898. Serial No. 666,823. (No model.)

of manufacturing the same, and has for its object to provide anefficient, durable, and cheap transfer-s11 rface which is light inweight and requires little space when kept in store.

and which maybe repeatedly used for transferring the drawing or otherdesign produced on the same to lithographic stones.

According to my invention I produce transfer-surfaces for lithographicpurposes as follows: I apply to a plane surface of metal, wood, leather,fabric, or paper, but preferably of cardboard of medium thickness, acoating or ground consisting of one thousand parts, by weight, of water,one hundred parts, by weight, of gelatin, one to five parts, by weight,of glycerin, and so much of zinc-white that the paste formed of theseingredients may be still applied to the surface by means of rollers. Ithen pour over such coating when dry a concentrated aqueous solution ofalum. When the whole has dried, I may again pour the alum solution overthe coating-and then dry it, and repeat this operation until the coatinghas become insoluble in cold water; but usually one or two treatmentswith alum solution will be found sufficient. The transfer-surface isthen ready for use. The proportions above given may vary considerablywithout affecting the result to be obtained.

The drawing or design to be transferred is drawn or otherwise producedon the transfersurface obtained as above described with ordinarylithographic ink or crayon (chalk) in any usual or desired manner, and,if desired, the transfer-surface is then coated with gum solution forbetter preserving the drawing. For transfer the gum coating is washedoff and transfer-ink is then applied to the transfer-surface in theusual way-via, after moistening such surface with a weak gum solution.After drying the transfer-surface is placed on the stone and the wholeis passed through the press once or twice. The transfer-surface is thentaken oi the stone, which can bedone without any difliculty and withoutin any way damaging the drawing or de sign on the transfer-surface andthe latter for reprinting.

I claim- 1. A process of manufacturing transfer surfaces forlithographic purposes consisting in applying to a plane surface ofmetal, wood, leather, fabric, paper or cardboard a coating of water,gelatin, glycerin and zinc-white mixed to form a paste, in thenalternately drying such coating and pouring over it a concentratedaqueous solution of alum and repeating these latter two operations untilsuchcoating has become insoluble in cold water.

2. As a new article of commerce a transfersurface for lithographicpurposes consisting of a backing of metal, wood, leather, fabric, paperor cardboard and of a coating thereon substantially consisting ofzinc-white, gelatin and glycerin such coating having been renderedinsoluble in cold water by alum.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

J OHANN ROTTACH.

Witnesses:

CARL ROTTACH, Orro ROSSMANILLY.

